Jamie Lokier wrote:
> I expect ioctls are not properly restricted for an O_NONE file, but I
> didn't try. It wouldn't be hard to simply avoid opening the underlying
> device -- thus allowing the fs-specific through to the fs.
Some uses of O_NONE (or "O_NOACCESS", as it's called sometimes) are in
avoiding access to a device (read-ahead, media detection, etc.) for
which we want to send ioctls:
- setfdprm: the driver may not know how to read the disk before the
ioctls are done
- fdformat: for obvious reasons
- LILO: fetch geometry data, even if the media is not around
Particularly fdformat is a good test if O_NONE still works :-)
BTW, O_NONE is about as old as Linux. Maybe we should eventually add it
to asm/fcntl.h, to avoid the regular threads on its feasibility ;-)
- Werner
-- _________________________________________________________________________ / Werner Almesberger, ICA, EPFL, CH werner.almesberger@ica.epfl.ch / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Fri Mar 24 2000 - 08:12:46 EST